Invasive garden ‘super ants’ take hold faster than ever in UK, new research finds

Posted on 26 July 2016

Three new infestations of an invasive garden ant - known for building massive colonies of tens of thousands of insects - have been found in the UK this year, with researchers at the University of York warning their impact on biodiversity could be huge.

Lasius neglectus (credit: Phillip Buckham-Bonnett)

First discovered in 2009, there are now a total of six known UK infestations of the Lasius neglectus which thrive in greenhouses and domestic gardens. Originating from Asia, they are likely to have arrived in the UK through the import of plants from infected areas.

The ants pose no threat to humans but non-indigenous species are capable of dramatically altering ecosystems and can drive native species to extinction. It is estimated that invasive species cost the UK £1.7billion every year through damage and management costs.

However, Dr Elva Robinson at the University of York believes many more sites are yet to be uncovered.

Since 2014, Robinson has worked alongside PhD student Phillip Buckham-Bonnett to establish the extent of the invasion in the UK. Their work has formed the basis of a Rapid Risk Assessment submitted to the government's Animal & Plant Health Agency in June.

Showing an increase in the rate of new 'super ant' discoveries, it offers recommendations for management on a national scale and will inform decision-making on UK biosecurity.

Despite its name, the super ant is smaller than the common native UK variety, but builds 'super' colonies with many queens and interconnected nests which can stretch for miles.

This trait allows the alien species to out-compete native ants commonly found in UK gardens. Living in extended colonies in large numbers, the super ant is able to out-compete for aphids and space.

The ant originated in Turkey and has since spread across the continent. It was first discovered in the UK at a National Trust property in Gloucestershire, where a colony of around 35,000 was found in 2009. The ant has subsequently been found in six other locations in the UK, including Eastbourne and Hendon, North London.

Five years later - and 100 miles east - the ants were discovered in a London home and another site was identified in Cambridgeshire. This year, the ants have been discovered in Yorkshire and two sites on the south coast. Robinson has found no obvious connection between the sites.

Dr Robinson, a Lecturer in Ecology in the Department of Biology at the University of York, said: "We think the invasive ants have the potential to have a big impact on the native ecosystem. In the sites we have studied, it is clear they are excluding the native ants. They are clearly dominating, and where they cluster, native species are being pushed out. So far, they have been discovered in gardens and glass houses, but we don't yet know whether these ants will be able to thrive outside areas of human habitation."

“Gaining a strong understanding of its new place in the native habitat will help manage the situation, and we are on the look-out for new sites in likely areas and can verify new sites as reported by pest control, as garden ants can be difficult for members of the public to identify.

"Apart from being slightly smaller, the invasive garden ant looks a lot like our common native garden ant so they can be difficult to recognise. These new ants are not aggressive, they do not sting and they pose no harm to humans beyond people finding it unpleasant to have an infestation."

At existing sites, gardeners are taking precautions to minimize the likelihood of furthering the colony.

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Research is being a carried out thanks to funding from NERC and Hymettus, which undertakes research and provides advice on the conservation of bees, wasps, ants and other invertebrates in the British Isles.